linux-kernel - Re: [PROBLEM] x86: result of verify_local

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20140209123907.GA21208@gmail.com>
Date:	Sun, 9 Feb 2014 13:39:07 +0100
From:	Ingo Molnar <mingo@...nel.org>
To:	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org
Subject: Re: [PROBLEM] x86: result of verify_local_APIC() is ignored


* Jon <nuxi@...lt24.org> wrote:

> In arch/x86/kernel/apic/apic.c there is a function called
> verify_local_APIC() that does some APIC checks. The part where it writes
> to the APIC ID register can cause CPU #15 to not come online under
> VMware ESXi on 32-bit kernels if the virtual hardware version is 8.
> 
> I noticed that Ingo actually removed this exact chunk of code from
> arch/i386/kernel/apic.c in 2.6.4, but since it was left in the x86_64
> copy it came back when the two were merged.
> http://permalink.gmane.org/gmane.linux.kernel.commits.head/27538
> 
> The Intel architecture manuals seem to agree and notes that the recent
> Intel CPUs do not allow writing to the register which means that
> machines are actually failing this check... which doesn't matter becuase
> none of the callers are checking the return value of this function
> anyway.

I guess we could remove that from the 64-bit code too. Would you like 
to send a tested patch?

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/